1. Field of the Invention
The present invention relates to a voice quality measurement device, method and computer readable medium storing a program, and may be employed in, for example, IP (internet protocol) phone terminals (including softphones).
2. Description of the Related Art
In recent years, IP phone communications, which is voice communications using VoIP (Voice over IP) technology, has become widespread. In IP phone communications, information of a voice signal is put into IP packets and the voice signals are transferred to a communication partner terminal by transmissions through an IP network. In general, real-time performance of transmissions in an IP network is not assured, and time variations of packets (jitter) and the like occur during voice packet transfers (during calls), leading to falls in call quality. Consequently, techniques for measuring conditions of voice quality are sought after. Methods for indexing voice quality on the basis of statistical information of packets transmitted during a call (statistical values of packet loss counts and jitter and the like) have been proposed, for example, as described in ITU-T, P. 564.
However, in contemporary IP phone communications, technologies that correct for time variations of packets (jitter) and the like occurring in a network are used at the receiving side. Thus, statistical information of packets passing through the network does not necessarily lead directly to an index of call quality.